/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.zookeeper.retry;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;

/**
 * A Class which extends {@link ZooKeeper} and will automatically retry calls to
 * zookeeper if a {@link KeeperException.ConnectionLossException} occurs
 */
public class ZooKeeperRetry extends ZooKeeper {

	private boolean closed = false;
	private final Watcher watcher;
	private int limit = -1;

	/**
	 * @param connectString
	 * @param sessionTimeout
	 * @param watcher
	 * @throws IOException
	 */
	public ZooKeeperRetry(String connectString, int sessionTimeout,
			Watcher watcher) throws IOException {
		super(connectString, sessionTimeout, watcher);
		this.watcher = watcher;
	}

	/**
	 * @param connectString
	 * @param sessionTimeout
	 * @param watcher
	 * @param sessionId
	 * @param sessionPasswd
	 * @throws IOException
	 */
	public ZooKeeperRetry(String connectString, int sessionTimeout,
			Watcher watcher, long sessionId, byte[] sessionPasswd)
			throws IOException {
		super(connectString, sessionTimeout, watcher, sessionId, sessionPasswd);
		this.watcher = watcher;
	}

	@Override
	public synchronized void close() throws InterruptedException {
		this.closed = true;
		super.close();
	}

	@Override
	public String create(String path, byte[] data, List<ACL> acl,
			CreateMode createMode) throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.create(path, data, acl, createMode);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
				if (exists(path, false) != null) {
					return path;
				}
			} catch (KeeperException.NodeExistsException e) {
				return path;
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public void delete(String path, int version) throws InterruptedException,
			KeeperException {
		int count = 0;
		do {
			try {
				super.delete(path, version);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
				if (exists(path, false) == null) {
					return;
				}
			} catch (KeeperException.NoNodeException e) {
				break;
			}
		} while (!closed && (limit == -1 || count++ < limit));
	}

	@Override
	public Stat exists(String path, boolean watch) throws KeeperException,
			InterruptedException {
		int count = 0;
		do {
			try {
				return super.exists(path, watch ? watcher : null);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public Stat exists(String path, Watcher watcher) throws KeeperException,
			InterruptedException {
		int count = 0;
		do {
			try {
				return super.exists(path, watcher);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public List<ACL> getACL(String path, Stat stat) throws KeeperException,
			InterruptedException {
		int count = 0;
		do {
			try {
				return super.getACL(path, stat);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public List<String> getChildren(String path, boolean watch)
			throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.getChildren(path, watch ? watcher : null);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return new ArrayList<String>();
	}

	@Override
	public List<String> getChildren(String path, Watcher watcher)
			throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.getChildren(path, watcher);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return new ArrayList<String>();
	}

	@Override
	public byte[] getData(String path, boolean watch, Stat stat)
			throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.getData(path, watch ? watcher : null, stat);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public byte[] getData(String path, Watcher watcher, Stat stat)
			throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.getData(path, watcher, stat);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public Stat setACL(String path, List<ACL> acl, int version)
			throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.setACL(path, acl, version);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
				Stat s = exists(path, false);
				if (s != null) {
					if (getACL(path, s).equals(acl)) {
						return s;
					}
				} else {
					return null;
				}
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	@Override
	public Stat setData(String path, byte[] data, int version)
			throws KeeperException, InterruptedException {
		int count = 0;
		do {
			try {
				return super.setData(path, data, version);
			} catch (KeeperException.ConnectionLossException e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
				Stat s = exists(path, false);
				if (s != null) {
					if (getData(path, false, s) == data) {
						return s;
					}
				} else {
					return null;
				}
			}
		} while (!closed && (limit == -1 || count++ < limit));
		return null;
	}

	/**
	 * @param limit
	 */
	public void setRetryLimit(int limit) {
		this.limit = limit;
	}

	/**
	 * @return true if successfully connected to zookeeper
	 */
	public boolean testConnection() {
		int count = 0;
		do {
			try {
				return super.exists("/", null) != null;
			} catch (Exception e) {
				System.out
						.println("ZooKeeper connection lost.  Trying to reconnect.");
			}
		} while (count++ < 5);
		return false;
	}

}